The present disclosure is directed to circuits and methods for transmission of power and control signals through a single circuit isolation element, such as a coupled inductor.
In many electrical circuits, electrical isolation of one portion of a circuit from another portion of the circuit may be desired. Electrical isolation may be desired for any of a number of reasons, such as protection against electric shock, suppression of electrical noise in sensitive devices, and to transfer power between two circuits which must not be connected together, to name a few. Various different isolation devices are commonly used, such as optically isolated amplifiers and isolation transformers, for example.
An isolation transformer is a transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source, commonly for safety reasons. Isolation transformers provide galvanic isolation and may be used to protect against electric shock, to suppress electrical noise in sensitive devices, or to transfer power between two circuits which must not be connected together. Furthermore, suitably designed isolation transformers block interference caused by ground loops, and isolation transformers with electrostatic shields may be used for power supplies for sensitive equipment such as computers or laboratory instruments.
One common use of an electrically isolated circuit is in isolated gate drivers for power switches, such as power MOSFETs. Such isolated gate drivers may be constructed using a gate drive transformer that drives the gate directly. Traditional isolated gate drivers use a transformer to provide drive power, and a different mechanism to provide the control signal for controlling the switching of the gate.